Carburetor



y 1961 A. H. WINKLER 2,991,986

CARBURETOR Filed March 15, 1960 INVENTOR.

ALBERT H. WINKLER AT TORNE! Y United States Patent 2,991,986 CARBURETORAlbert H. Winkler, Elmira, N.Y., assignor to The Bendix Corporation, acorporation of Delaware Filed Mar. 15, 1960, Ser. No. 15,161 5 Claims.(Cl. 261-46) The present invention relates to carburetors for internalcombustion engines and more particularly to an enrichment system forsupplying an enriched mixture to the engine when the choke is closed orpartially closed.

It is an object of the present invention to provide increased fuel flowthrough the carburetor idle system during starting and warmup operationof the engine.

Other objects and advantages of the present invention will becomeapparent from the following description taken in connection with theappended drawings where- FIGURE 1 is a sectional view of a carburetorembodying the present invention; and

FIGURE 2 is a sectional view taken along line 22 of FIGURE 1.

Referring now to the drawings, numeral designates a carburetor, 12 aninduction passage, 14 a choke valve, 16 a throttle and 18 a fuel bowl. Amain discharge jet 20 discharges fuel from bowl 18 into the throat ofventuri 22 formed in induction passage 12.

Idle ports 24 and 26 open into the induction passage on opposite sidesof throttle 16 when in closed position and are connected to the fuelbowl 18 by means conduit 28 and idle tube 30. A calibrated air bleedvent 32 connects the upper portion of conduit 28 with the inductionpassage 12. Vent 32 acts to prevent syphoning from occurring in the idlesystem and also as an air bleed to emulsify the fuel. A second air bleedpassage 34 of larger effective area than vent 32 connects conduit 28with a port 36 in the side wall of cylinder 38 of the automatic chokedesignated generally by the numeral 40.

The automatic choke includes a thermostat 42 mounted on the carburetorand engaging choke lever 44 to urge the choke toward closed positionwhen cold. A piston 46 is reciprocably mounted in cylinder 38 and isconnected to choke lever 44 by means of rod 48. Cylinder 38 is closed atone end 50 and is connected near its closed end to the induction passagedownstream of the throttle by means of conduit 52. The other end 54 ofcylinder 38 opens into the induction passage upstream of choke valve 14.A pair of diametrically opposed, longitudinal grooves 56 and 58 areformed in the side walls of piston 46. Grooves 56 and 58 open at the endof piston 46 exposed to the open end 54 of cylinder 38 and terminate inspaced relation to the end of piston 46 exposed to the closed end 50 ofcylinder 38. A circumferential groove 60 is formed in the piston toconnect grooves 56 and 58. As shown in the solid line position in FIGURE1, piston 46 is located in cylinder 38 so that port 36 is open when thechoke is opened; and, as shown in the dotted line position in FIGURE 1,piston 46 is positioned to close port 36 when the choke is closed.

In operation, thermostat 42 when cold urges the choke valve 14 towardclosed position and piston 46 is positioned to closed bleed port 36.Upon starting of the engine, the induction passage pressure below thethrottle will be reduced causing the piston 46 to move to the right topartially open the choke valve in opposition to the thermostat. Port 36is located in the wall of cylinder 38 so as to be closed by the piston46 until the choke valve has opened a predetermined amount. While idlebleed port 36 is closed, the idle system will discharge an increasedamount of fuel through one or more of the "ice idle ports 24 and 26.Upon opening of the choke beyond the predetermined position, the idlebleed port 36 will be opened and the amount of fuel discharged by theidle system will be reduced.

Under some circumstances, the low induction passage pressurecommunicated to cylinder 38 near its closed end 50 would be suflicientto draw fuel from the idle tube 30, bleed passage 34, between the sidewalls of piston 46 and cylinder 38 for discharge into the inductionpassage 12 through conduit 52. This condition would not only beunsatisfactory in supplying an excessively rich mixture but would alsocause gum deposits in the cylinder 38 leading to sticking of the piston46 and improper functioning of the automatic choke 40. The grooves 56,58 and 60 are interposed in the piston between the low pressure conduit52 and the idle bleed port 36 to break any suction that might otherwiseoccur at the port i.e. should there be leakage between the walls of thepiston 46 and cylinder 38 it will be air leakage through the grooves 56,58 and 60 rather than a fuel leakage from idle bleed port 36.

While only one embodiment of my invention has been shown and describedvarious changes and arrangements of parts may be made without departingfrom the spirit of the invention.

I claim:

1. In a carburetor, a fuel bowl, an induction passage, a choke valve anda throttle in said passage, a cylinder having an open end and a closedend, a piston in said cylinder operatively connected to said chokevalve, a conduit connecting said cylinder near its closed end with asource of vacuum, a fuel passage connecting said fuel bowl with theinduction passage downstream of said throttle, and an air passageconnecting said fuel passage to said cylinder intermediate the endsthereof, said piston being adapted to close said air passage when thechoke valve is closed and to open said air passage when the choke valveis opened.

2. In a carburetor, a fuel bowl, an induction passage, a choke valve anda throttle in said passage, a cylinder having an open end and a closedend, a piston in said cylinder operatively connected to said chokevalve, a conduit connecting said cylinder near its closed end with theinduction passage downstream of the throttle, a fuel passage connectingsaid fuel bowl with the induction passage downstream of said throttle,an air passage connecting said fuel passage to said cylinderintermediate the ends thereof, said piston being adapted to close saidair passage when the choke valve is closed and to open said air passagewhen the choke valve is opened and a second continuously open airpassage of smaller effective flow area than said first mentioned airpassage connecting said fuel passage with said induction passage.

3. In a carburetor, a fuel bowl, an induction passage, a choke valve anda throttle in said passage, a cylinder having an open end and a closedend, a piston in said cylinder operatively connected to said chokevalve, a conduit connecting said cylinder near its closed end with theinduction passage downstream of said throttle, a

fuel passage connecting said fuel bowl with the induction passage, andan air passage connecting said fuel p assage to said cylinderintermediate the ends thereof, said piston being adapted to close saidair passage when the choke valve is closed and to open said air passagewhen the choke valve is opened.

4. In a carburetor, a fuel bowl, an induction passage, a choke valve anda throttle in said passage, a cylinder having an open end and a closedend, a piston in said cylinder operatively connected to said chokevalve, a conduit connecting said cylinder near its closed end with theinduction passage downstream of the throttle, a fuel passage connectingsaid fuel bowl to said induction passage downstream of said throttle, aport in said cylinder, an air passage connecting said port to said fuelpassage, said piston being adapted to close said port when said chokevalve is closed and to open said port when the choke valve is opened,and a longitudinal groove formed in'said piston circumferentially spacedfrom said port, said groove communicating with the open end of saidcylinder and terminating in spaced relation to the other end of thepiston.

5. In a carburetor, a fuel bowl, an induction passage, a choke valve anda throttle in said passage, a cylinder having an open end and a closedend, a piston in said cylinder operatively connected to said chokevalve, a conduit connecting said cylinder near its closed end with theinduction passage downstream of the throttle, a fuel passage connectingsaid fuel bowl to the induction pas sage, a port in said cylinderintermediate the ends thereof, an air passage connecting said port tosaid fuel passage, said piston being adaptcd to close said port whensaid choke valve is closed and to open said port when the choke valve isopened, a pair of longitudinal grooves formed in said pistoncircumferentially spaced from said port, said grooves communicating withthe open end of said cylinder and terminating in spaced relation to theother end of the piston and a circumferentially disposed groove in saidpiston connecting said longitudinal grooves.

References Cited in the file of this patent UNITED STATES PATENTS

